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In SI units, permeability is measured in henries per meter (H/m), or equivalently in newtons per ampere squared (N/A 2). The permeability constant μ 0 , also known as the magnetic constant or the permeability of free space, is the proportionality between magnetic induction and magnetizing force when forming a magnetic field in a classical vacuum .
It is a physical constant, conventionally written as μ 0 (pronounced "mu nought" or "mu zero"). It quantifies the strength of the magnetic field induced by an electric current. Expressed in terms of SI base units, it has the unit kg⋅m⋅s −2 ⋅A −2. It can be also expressed in terms of SI derived units, N⋅A −2.
kg⋅m 2 ⋅s −2 ⋅A −1: H magnetic field strength ampere per metre: A/m A⋅m −1: F magnetomotive force: ampere: A = Wb/H A R magnetic reluctance: inverse henry: H −1 = A/Wb kg −1 ⋅m −2 ⋅s 2 ⋅A 2: P magnetic permeance: henry: H = Wb/A kg⋅m 2 ⋅s –2 ⋅A –2: L, M inductance: henry: H = Wb/A = V⋅s/A kg⋅m 2 ⋅s −2 ...
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.
But for the equations with source terms (Gauss's law and the Ampère-Maxwell equation), the Hodge dual of this 2-form is needed. The Hodge star operator takes a p-form to a (n − p)-form, where n is the number of dimensions. Here, it takes the 2-form (F) and gives another 2-form (in four dimensions, n − p = 4 − 2 = 2).
The constants listed here are known values of physical constants expressed in SI units; that is, physical quantities that are generally believed to be universal in nature and thus are independent of the unit system in which they are measured.
In classical electromagnetism, magnetization is the vector field that expresses the density of permanent or induced magnetic dipole moments in a magnetic material. Accordingly, physicists and engineers usually define magnetization as the quantity of magnetic moment per unit volume. [1]
The definition can be expressed as follows: = where R {\displaystyle {\mathcal {R}}} ("R") is the reluctance in ampere-turns per weber (a unit that is equivalent to turns per henry ). " Turns " refers to the winding number of an electrical conductor comprising an inductor.